Existing approaches to forming a thermal barrier on an exhaust duct of a gas turbine engine, such as an auxiliary power unit (APU), typically involve multiple levels of sandwich material with air spacing around the exhaust duct wall. The use of multiple layers of material increase weight and cost. Any high temperature areas exposed must be covered, which sometimes requires the use of extra thermal blankets which are bulky and expensive.
There is thus a need for a new thermal shield arrangement.